Currently, diagnosis of sepsis and shock is comprehensively determined on the basis of clinical aspects, vital signs, a blood test, imaging examination, and the like.
The clinical aspects such as mental deterioration, a change in skin color, a reduction in urine volume, a capillary refill time, and the like are verified, and the vital signs such as a blood pressure, a heart rate, a breathing rate, a body temperature, and the like are observed. A blood leukocyte number, C-reactive protein (CRP), procalitonin, lactate, a liver somatic index, a kidney number, and the like are examined through the blood test, and bacteria, fungi, and the like are detected through a blood culture test. A lesion is verified by the imaging examination using plain roentgenography, computerized tomography (CT), magnetic resonance imaging (MRI), and the like.
Particularly, it is known that early diagnosis and treatment of sepsis and shock are very important. In fact, a mortality rate of patients who received antibiotics within one hour in sepsis was 19.5%, while a mortality rate of patients who did not receive antibiotics was 33.2%.
A related art is disclosed in Korean Patent Laid-Open Application No. 2005-0016987 (published on Feb. 21, 2005, entitled “Method for diagnosing sepsis using mitochondrial nucleic acid analysis”). However, the above-described conventional method is inevitably delayed in diagnosis.
Recently, in order to overcome such problems, techniques for diagnosing sepsis and shock through other methods have been developed.
A microcirculatory disorder is well known as major pathophysiology of sepsis and shock, and the microcirculatory disorder may be early detected even through other indexes such as a blood pressure and the like are normal.
When sepsis occurs, a blood flow rate of a body becomes relatively insufficient. Therefore, in order to maintain blood flow rates in important organs such as a heart, a brain, and the like, a self-protective mechanism acts to reduce blood flow rates in relatively less important organs such as skin, a gastrointestinal tract, muscles, and the like.
For this reason, a microcirculatory disorder is early detected compared with other indexes, and when the detected microcirculatory disorder is utilized, early diagnosis of sepsis and shock is possible, and in order for early diagnosis of sepsis and shock, there is also commercialization of health screening equipment so as to verify a microcirculatory disorder.
Typically, there are orthogonal polarization spectroscopy (OPS) and sidestream dark field (SDF) imaging. These equipment observe a microcirculatory change in a sublingual mucosa.
However, in the case of OPS and SDF imaging, a microcirculatory flow is measured at a sublingual mucosa, and there is a difference in the results depending on an observer in the microcirculatory flow measurement. OPS and SDF imaging perform a measurement by bringing an instrument into contact with a sublingual mucosa membrane, and thus the result depends on a force of the observer bring the instrument into contact with the sublingual mucosa membrane, and when the instrument is slightly strongly brought into contact with the sublingual mucosa membrane, capillaries are pressed and thus a blood flow is erroneously measured as not being present.
Therefore, there is a limit to objectively use OPS and SDF imaging, and thus it is necessary to develop a diagnostic technique capable of measuring a microcirculatory flow in a non-contact manner.